ALTERNATIVE AND ECOLOGICAL FUELS. A REVIEW

This article is a literature review on alternative and ecological fuels, and its production, combustion, performance and emissions. The study is based on the reports of many researchers who published their results between 1999 and 2008. As the conventional fuels and oils are depleting day by day there is a need to find out an alternative fuels and oils to fulfill the energy demand of the world. Biodiesel, methanol, ethanol, hydrogen are the best available sources to fulfill the energy demand. The scientists and researchers conducted tests by using different sources to alternative fuels production and their blends with conventional fuels. Most of the scientists reported that short-term engine tests using different kind of vegetable oils were very promising, but the long-term test results showed higher carbon build up and lubricating oil contamination resulting in engine failure. It was reported that the combustion characteristics of alternative fuels like biofuels are similar as conventional fuels and blends were found to have shorter ignition delay, higher ignition temperature, and higher ignition temperature and peak heat release. The engine power output was found to be equivalent to that of conventional diesel fuel and it observed that the base catalysts in biodiesel production schemes are more effective than acid catalysts and enzymes. This review discussed also some of the processes that are being developed as an alternative to present-day hydrodesulphurisation processes that are based on heterogeneous catalysis. The technologies applied in these alternatives range from adsorption, oxidation to simple physical separation methods - non-destructive adsorption, extraction.